Blumea 55, 2010: 65–67 www.ingentaconnect.com/content/nhn/blumea RESEARCH ARTICLE doi:10.3767/000651910X499178

A new species of Argostemma () from Mount Victoria, Myanmar

N. Tanaka1, T. Ohi-Toma2, J. Murata2

Key words Abstract Argostemma victorianum (Rubiaceae) is described and illustrated as a new species from the Natma Taung (Mt Victoria) National Park, western Myanmar. It is characterized by the combination of solitary or 2-flowered Argostemma inflorescence with indistinct peduncle, relatively large, white, bell-shaped flowers in comparison with the small Myanmar size of the , and having globose tubers. This species is epiphytic on wet and densely mossy tree trunks at Rubiaceae c. 2 500 m altitude on Mt Victoria. subfamily tribe Argostemmateae Published on 16 April 2010

INTRODUCTION Plant (4–)6–8 cm tall, epiphytic on densely mossy tree trunks. Rhizomes (tuber) globose, 0.4–0.9 cm diam. Stem Field expeditions to the Natma Taung (Mt Victoria) National erect, unbranched, glabrous. Leaves opposite, usually in one Park, Chin State, western Myanmar have been conducted by extremely anisophyllous pair, occasionally in pseudo-whorled a team from the Makino Botanical Garden and the Botanical arrangement of 2 pairs, elliptic, acute at base, 0.7–2(–4) cm Gardens of the University of Tokyo, in cooperation with the For- long, 0.2–0.3 cm wide, midrib with several pairs of ascending est Department, Union of Myanmar Ministry of Forestry, since prominent lateral veins, hairy on upper surface, glabrous on 2002. The Natma Taung National Park is located in the south- lower surface, sessile; stipules ovate, 4–5 mm long, 1–3 mm western part of Myanmar, in the so-called ‘Chin Hills’. Mount wide, pubescent along margin and lower surface. Inflorescence Victoria (21°12' N, 93°35' E) is the highest mountain (3 053 of a single or occasionally of two flowers. Flowers 5-merous, m) in this range, which extends northwards along the western slightly zygomorphic, 1–1.8 cm diam, 1–2 cm long; calyx border of the country, adjoining the Himalayas in northeast 5-lobed, persistent; calyx lobes 5, slightly fimbriate, 0.5 cm long, India and Kachin State, where the towering Mt Khakaborazi 0.2 cm wide; corolla white, bell-shaped with short tube, lobes is located. Mount Victoria is regarded as an ecological island, 5, spreading venation conspicuous, entirely glabrous; corolla offering a temperate climate that is otherwise absent in the lobes 0.5–0.8 cm long, acute at apex; corolla tube 3–5 mm vicinity (Tanaka 2005). During an expedition in 2002, an unde- long; pedicels 1.5–2 cm long; stamens 5 inserted to the base scribed species of the Argostemma Wall. (Rubiaceae) of corolla tube; anthers dull yellow, 3 mm long, c. 0.7 mm wide; was discovered. It is described as Argostemma victorianum filaments 3–4 mm long, free; ovary inferior, globose, 2-locular, and illustrated here. with many ovules, on axillary placenta; style filiform, 6–8 mm Argostemma is a genus containing over 200 species of peren- long; stigma not lobed, capitate. Fruits unknown. nial herbs (Bremer 1989), belonging to the subfamily Rubio- Distribution — West Myanmar (Mt Victoria). ideae tribe Argostemmateae Bremek. ex Verdc. (Bremer 1987, Habitat & Ecology — Epiphytic on wet and densely mossy Bremer & Manen 2000). In the system of Bremer & Manen tree trunks in moist evergreen forest, c. 2 500 m in altitude. (2000), the members of the tribe consist of two genera, namely, Notes — Thus far known only from the type locality. Since Argostemma and Mycetia. The genus Argostemma is distrib- further floristic research in other areas within the Natma Taung uted widely in tropical and subtropical Asia with two species in National Park failed to locate this species, it is likely to be rare. west tropical Africa (Robbrecht 1988, Bremer 1989, Mabberley Argostemma victorianum is clearly characterised by a combina- 1997, Sridith 1999, Sridith & Puff 2000). From Myanmar, thus tion of solitary or 2-flowered inflorescence with indistinct pe- far six species have been recorded (Kress et al. 2003). duncle, relatively larger, white, bell-shaped flowers, compared to the small size of the plant, and also globose tubers. The specific epithet is named after the type locality, Mt Victoria. Argostemma victorianum Nob.Tanaka, sp. nov. — Fig. 1, 2 We also examined the sequences of rbcL gene, atpB-rbcL re- Ab omnibus speciebus generis Argostemmatis planta tota exigua, 6–8 gion and rps16 intron of the new species, using the published cm alta cum flora majore, 1–1.8 cm diametro et tubere globoso ferente primers of each region. The DNA extraction, PCR amplification differt. — Typus: N. Tanaka, T. Sugawara, N. Murakami, K. Aoki, S. Sakai, K. Watanabe & Khin Myo Htwe 023632 (holo MBK; iso RAF, TI), Myanmar, and sequence detection were performed using the procedure Chin State, along roadside between Mt Victoria and Mindat, 2500–2550 m of Ohi-Toma et al. (2006). Sequences determined in this study alt., 8 June 2002. were registered with the DNA Data Bank of Japan (DDBJ), which is linked to GenBank (accession numbers: AB444629 for rbcL, AB444630 for atpB-rbcL, AB44631 for rps16 intron). 1 Department of Botany, Kochi Prefectural Makino Botanical Garden, Godai- san 4200-6, Kochi 781-8125, Japan; Further study will be required to clarify the phylogenetic rela- corresponding author e-mail: [email protected]. tionship of the new species. 2 Botanical Gardens, Graduate School of Sciences, the University of Tokyo, Hakusan 3-7-1, Bunkyo-ku, Tokyo 112-0001, Japan.

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g e

d f

a b

c

Fig. 1 Argostemma victorianum Nob.Tanaka. a. Habit; b. side view of inflorescence; c. side view of flower; d. bract; e. stamens and style; f. stamens; g. style (all: N. Tanaka et al. 023632, MBK). — Scale bars: a = 5 mm; b–e = 3 mm; f, g = 1 mm. N. Tanaka et al.: A new species of Argostemma from Mount Victoria 67

a b Fig. 2 Habit of Argostemma victorianum Nob.Tanaka. The plant is epiphytic on densely mossy tree trunks at c. 2 500 m altitude, Natma Taung National Park, western Myanmar. a. Front view of the plant; b. side view of the plant.

Acknowledgements The authors thank U Tun Paw Oo, director of Nature Ohi-Toma T, Sugawara T, Murata H, Wanke S, Neinhuis C, Murata J. 2006. and Wildlife Conservation Division, U Soe Win Hlaing, director general, Forest Molecular phylogeny of Aristolochia sensu lato (Aristolochiaceae) based Department, Union of Myanmar Ministry of Forestry for their arrangement of on sequences of rbcL, matK, and phyA genes, with special reference to dif- our field research, Ms. M. Nakajima for preparing the illustrations, and Prof. ferentiation of chromosome numbers. Systematic Botany 31: 481–492. Tetsuo Koyama for reviewing the Latin diagnosis. We also thank Stephan Robbrecht E. 1988. Tropical woody Rubiaceae. Opera Botanica Belgica Gale for his help and the Board of Trustees of the Royal Botanic Gardens, 1: 1–271. Kew, for providing digital images for comparative analyses in the genus Sridith K. 1999. A synopsis of the genus Argostemma Wall. (Rubiaceae) in Argostemma. This research is supported by Grant-in-Aid from the Japan Thailand. Thai Forest Bulletin, Botany 27: 86–137. Society for the Promotion of Science for Scientific Research (A) to Prof. Jin Sridith K, Puff C. 2000. Distribution of Argostemma Wall. (Rubiaceae), with Murata (13375003 & 17255004) and Grant-in-Aid from Kochi Prefectural special reference to Thailand and surrounding areas. Thai Forest Bulletin, Government. Botany 28: 123–137. Tanaka N. 2005. Plant inventory research: Contributions to the Flora of Myanmar. Acta Phytotaxonomica et Geobotanica 56: 21–26. REFERENCES

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